Motors are apparatuses which convert electrical energy into rotational energy using a force received by a conductor in a magnetic field. Recently, as a use of the motor expands, a role of the motor becomes important. Particularly, as the number of electrical devices in vehicles rapidly increases, demand for the motor applied to a steering system, a braking system, a safety critical system, and the like is greatly increasing.
Particularly, a case in which an external force is applied to a motor in a direction of a shaft is increasing. Accordingly, motors combined with a bearing configured to support a load in a direction of a shaft, such as an angular bearing, and a wave washer have been suggested.
However, when vibrations are continuously applied to a motor and the motor is repeatedly driven, abraded materials may be discharged from a motor housing, a wave washer, a bearing, and the like. In the case in which such abraded materials exit the motor to the outside, the abraded materials may fatally affect the performance of a driving apparatus, a measurement apparatus, or other application apparatuses, such as a gear or sensor, adjacent to the motor. Particularly, in the case in which the abraded materials come into contact with the sensor, there may be a problem in that driving of the motor is delayed or the motor is not driven.